1 /* 2 * libzvbi -- Bit slicer 3 * 4 * Copyright (C) 2000-2007 Michael H. Schimek 5 * 6 * This library is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Library General Public 8 * License as published by the Free Software Foundation; either 9 * version 2 of the License, or (at your option) any later version. 10 * 11 * This library is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Library General Public License for more details. 15 * 16 * You should have received a copy of the GNU Library General Public 17 * License along with this library; if not, write to the 18 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 19 * Boston, MA 02110-1301 USA. 20 */ 21 22 /* $Id: bit_slicer.h,v 1.11 2008/02/24 14:18:13 mschimek Exp $ */ 23 24 #ifndef __ZVBI_BIT_SLICER_H__ 25 #define __ZVBI_BIT_SLICER_H__ 26 27 #include "sampling_par.h" 28 29 VBI_BEGIN_DECLS 30 31 /** 32 * @addtogroup BitSlicer 33 * @{ 34 */ 35 36 /** 37 * @brief Modulation used for VBI data transmission. 38 */ 39 typedef enum { 40 /** 41 * The data is 'non-return to zero' coded, logical '1' bits 42 * are described by high sample values, logical '0' bits by 43 * low values. The data is last significant bit first transmitted. 44 */ 45 VBI3_MODULATION_NRZ_LSB, 46 47 /** 48 * 'Non-return to zero' coded, most significant bit first 49 * transmitted. 50 */ 51 VBI3_MODULATION_NRZ_MSB, 52 53 /** 54 * The data is 'bi-phase' coded. Each data bit is described 55 * by two complementary signalling elements, a logical '1' 56 * by a sequence of '10' elements, a logical '0' by a '01' 57 * sequence. The data is last significant bit first transmitted. 58 */ 59 VBI3_MODULATION_BIPHASE_LSB, 60 61 /** 'Bi-phase' coded, most significant bit first transmitted. */ 62 VBI3_MODULATION_BIPHASE_MSB 63 } vbi3_modulation; 64 65 /** 66 * @brief Bit slicer context. 67 * 68 * The contents of this structure are private. 69 * Call vbi3_bit_slicer_new() to allocate a bit slicer context. 70 */ 71 typedef struct _vbi3_bit_slicer vbi3_bit_slicer; 72 73 typedef enum { 74 VBI3_CRI_BIT = 1, 75 VBI3_FRC_BIT, 76 VBI3_PAYLOAD_BIT 77 } vbi3_bit_slicer_bit; 78 79 /** 80 * @brief Bit slicer sampling point. 81 * 82 * This structure contains information about 83 * a bit sampled by the bit slicer. 84 */ 85 typedef struct { 86 /** Whether this struct refers to a CRI, FRC or payload bit. */ 87 vbi3_bit_slicer_bit kind; 88 89 /** Number of the sample times 256. */ 90 unsigned int index; 91 92 /** Signal amplitude at this sample, in range 0 to 65535. */ 93 unsigned int level; 94 95 /** 0/1 threshold at this sample, in range 0 to 65535. */ 96 unsigned int thresh; 97 } vbi3_bit_slicer_point; 98 99 extern vbi_bool 100 vbi3_bit_slicer_slice_with_points 101 (vbi3_bit_slicer * bs, 102 uint8_t * buffer, 103 unsigned int buffer_size, 104 vbi3_bit_slicer_point *points, 105 unsigned int * n_points, 106 unsigned int max_points, 107 const uint8_t * raw) 108 _vbi_nonnull ((1, 2, 4, 5, 7)); 109 extern vbi_bool 110 vbi3_bit_slicer_slice (vbi3_bit_slicer * bs, 111 uint8_t * buffer, 112 unsigned int buffer_size, 113 const uint8_t * raw) 114 _vbi_nonnull ((1, 2, 4)); 115 extern vbi_bool 116 vbi3_bit_slicer_set_params (vbi3_bit_slicer * bs, 117 vbi_pixfmt sample_format, 118 unsigned int sampling_rate, 119 unsigned int sample_offset, 120 unsigned int samples_per_line, 121 unsigned int cri, 122 unsigned int cri_mask, 123 unsigned int cri_bits, 124 unsigned int cri_rate, 125 unsigned int cri_end, 126 unsigned int frc, 127 unsigned int frc_bits, 128 unsigned int payload_bits, 129 unsigned int payload_rate, 130 vbi3_modulation modulation) 131 _vbi_nonnull ((1)); 132 extern void 133 vbi3_bit_slicer_set_log_fn (vbi3_bit_slicer * bs, 134 vbi_log_mask mask, 135 vbi_log_fn * log_fn, 136 void * user_data) 137 _vbi_nonnull ((1)); 138 extern void 139 vbi3_bit_slicer_delete (vbi3_bit_slicer * bs); 140 extern vbi3_bit_slicer * 141 vbi3_bit_slicer_new (void) 142 _vbi_alloc; 143 144 /* Private */ 145 146 typedef vbi_bool 147 _vbi3_bit_slicer_fn (vbi3_bit_slicer * bs, 148 uint8_t * buffer, 149 vbi3_bit_slicer_point *points, 150 unsigned int * n_points, 151 const uint8_t * raw); 152 153 /** @internal */ 154 struct _vbi3_bit_slicer { 155 _vbi3_bit_slicer_fn * func; 156 157 vbi_pixfmt sample_format; 158 unsigned int cri; 159 unsigned int cri_mask; 160 unsigned int thresh; 161 unsigned int thresh_frac; 162 unsigned int cri_samples; 163 unsigned int cri_rate; 164 unsigned int oversampling_rate; 165 unsigned int phase_shift; 166 unsigned int step; 167 unsigned int frc; 168 unsigned int frc_bits; 169 unsigned int total_bits; 170 unsigned int payload; 171 unsigned int endian; 172 unsigned int bytes_per_sample; 173 unsigned int skip; 174 unsigned int green_mask; 175 176 _vbi_log_hook log; 177 }; 178 179 extern void 180 _vbi3_bit_slicer_destroy (vbi3_bit_slicer * bs) 181 _vbi_nonnull ((1)); 182 extern vbi_bool 183 _vbi3_bit_slicer_init (vbi3_bit_slicer * bs) 184 _vbi_nonnull ((1)); 185 186 /** @} */ 187 188 VBI_END_DECLS 189 190 #endif /* __ZVBI_BIT_SLICER_H__ */ 191 192 /* 193 Local variables: 194 c-set-style: K&R 195 c-basic-offset: 8 196 End: 197 */ 198